1. Field of the Invention
The present invention relates to a mobile communication system and more particularly to a method of automatically assigning signaling terminals between a switching center and a base station.
2. Description of Related Art
Generally, a mobile communication system is a system allowing for communications during motion. A code division multiple access (CDMA) mobile communication system converts sequential analog signals into codes for transmission. This CDMA system provides a mobile communication mode which is convenient in processing noise and has an advantage of a little power consumption.
FIG. 1 shows a structure of the international telecommunications union-telecommunication sector (ITU-T) No. 7 signaling system in the typical mobile communication system.
As shown in FIG. 1, a base station (BS) 10 for transmitting and receiving messages to and from terminal equipment and switching centers and managing resources and a mobile switching center (MSC) 15 connected to the base station 10, for connecting subscribers 1 and operating for mobile communication services such as a function of charging for use of the system, respectively comprise: first and second base station application parts (B SAP) 11 and 16 dually designed (active and standby) for processing origination and destination of each mobile call, managing the resources, and transmitting subscriber's mobile managing messages; first and second signaling connection control parts (SCCP) 12 and 17 having dual structure, for performing a switch network data service, connection mode service for transferring control information between network management centers, a connectionless mode service for mobile calls, and a routing processing function; and first and second message transfer parts (MTP) 13 and 18 having a dual structure for processing a signaling message and performing a signaling network management function for error recovery and process on the process route of the processed signaling message.
FIG. 2 is a block diagram of hardware supporting a function of the typical ITU-T No. 7 signaling system, particularly, an access switch subsystem mobile (ASS-M) falling under an access switch subsystem (ASS) of the HDPX-300 (the Hyundai PCS exchange).
As shown in FIG. 2, the hardware comprises: a main processor & duplication control board assembly (MPDA.about.21 to 23 designed in dual which has software for managing the BSAP 11, 26, SCCP 12, 17, and MTP 13, 26; a signaling system process board assembly (SSPA) 24 to 16 designed in dual which has software for processing a level 3 of the MTP 13, 18 and connection and connectionless mode messages of the SCCP 12, 17 in the MPDA 21; and a signaling system firmware board assembly (SSFA) 27 to 29 designed in dual which has software for a level 2 of the MTP 13,18 in the MPDA 21 and four firmwares.
The MPDA 21 to 23 correspond to an ASS-M access switching processor (ASP), and the SSPA 24 to 26 correspond to the base station application part (BSAP).
Such ASS-M connects to a base station controller and performs a function of processing mobile subscribers calls and managing mobility, a self-maintenance function, a function of transmitting signal information to the base station, mobile station, and base station controller, and a traffic data transmitting function.
FIG. 3 shows a structure of software for supporting the functions of the typical ITU-T No. 7 signaling system.
As shown in FIG. 3, there exist: a base station application part (BSAP) 31 having a direct transfer application part (DTAP) and a base station management application part (BSMAP), for processing the origination and destination of mobile calls using the connection and connectionless mode services, managing the resources, and transmitting the subscriber's mobility managing messages; an internal network management part (B7INT) 32 for managing active and standby modes of a mobile signaling handling processor (MSHP), initializing and recovering data of the MSHP, and managing L2 (level 2) firmware of the SSFA 27; an SCCP management part (B7SMG) 33 for managing a signaling,point and subsystem of the SCCP 12, 17 in the other office and a subsystem of its own office; an MTP management part (B7NM) 34 for performing a signaling network managing function of recovering and processing errors on the process route of the signal message of the MTP 13, 18; an MSHP of ASS-M 35 having a BMHS 36 for providing the connection and connectionless mode services to the SCCP 12, 17 and processing the routing and a B7MH 37 for performing the signal message processing of the MTP 13, 18.
FIG. 4 is a block diagram showing a structure between the SSPA 24 to 26 and SSFA 27 to 29 depicted in FIG. 2.
As shown in FIG. 4, there exist: first to fourth SSFAs 41 to 44 having four firmwares, for serving a level 2 of the functions of the typical ITU-T No. 7 signaling system for transmission of signaling messages of the MPDA 21 to 23; first and second SSPAs 45 and 46 connecting to the first to fourth SSFA 41 to 44, for serving a level 3 of the typical ITU-T No. 7 signaling system's functions in the MPDA 21 to 23; first and second integrated global communication board assemblies (IGCAs) 47 and 48 connecting to the first and second SSPAs 45 and 46, for providing routes for processing the signaling messages of the MSHP 35.
The ITU-T No. 7 signaling system having such structure performs dual functions of active and standby modes, supports flow of messages through the protocol No. 7 in interlock of the switching center and base station, the interlock indicating that entities use the same hardware/software signals and parameters, and operates such that the MSHP 35, which is a processor of the SSPA 24, manages the SCCEI 12, 17 and MTP 13, 18 with conception of dualization. The MSHP 35 is a message handling processor for processing messages based upon the typical ITU-T No. 7 signaling system, the processor being one of auxiliary processors each having a unique functions in a switch, and more particularly, a hardware board for actually routing routing the messages received. The MSHP 35 is concerned with the messages, and the SSFA 41 to 44 performs a function of maintaining and supporting paths of the messages through connection to the other office in hardware.
An interface between the base station 10 and the mobile switching center 15, for supporting the international standard (IS)-634, supports open-system type interlock. The A-interface is standard for connection between the mobile switching center and control station in the mobile communication system, and there are standards A, B, C, and D defined according to each interlocked connection point once the system is constructed based upon the open protocol A-interface, it would be interlocked through the connection in hardware.
The MSHP 35 has idle, standby, acting, and active states and has information about a point of its own office, signaling point, signaling link, and subsystem. When two MSHPS 35 are used, one is in the active state and the other is in the standby state. When one MSHP 35 is used and the other is not in use, only the MSHP 35 in use becomes to be in the active state and the other becomes to be in the idle state. When the MSHP 35 converts from the idle state to the active or standby state, it stays at a wait state between the two states for a little while, which corresponds to the acting state.
Management of signaling terminals using a conventional load share method to manage such MSHP 35 is effected as follows.
The MSHP 35 is supposed to be in an activation or inactivation state. The MSHP 35 actually needs software for processing messages and data for routing the messages. The activation of the MSHP 35 indicates the state at the time point when the loading of the message processing software on the MSHP 35 is completed and the transmission of the routing data for process of the messages is completed after power is turned on in hardware.
Each MSHP 35 manages four signaling terminals. Two activated MSHPs 35 therefore manage eight signaling terminals.
When one activated MSHP 35 is converted into the inactivation state, the signaling terminals which are assigned to the MSHP 35 in hardware become to be inactivated, thus making the MSHP 35 useless. Then the other MSHP 35 in the activation state becomes to take charge of managing the signaling terminals which were under the management of the MSHP 35 previously in the activation state but now in the inactivation state. In this case, a single MSHP 35 is subject to management of eight signaling terminals. In other words, each MSHP 35 is designed to check the other's state periodically in an order of an operation system. Hence, when one is activated, the other recognizes this factor in real time and takes over the work of the inactivated MSHP 35.
However, when a signaling link is inactivated due to trouble in a signaling terminal which is assigned to the signaling link, another activated signaling terminal is not assigned to this inactivated signaling link, thus not being able to activate the signaling link in the conventional technology. When the SSFAs 41 to 44 having four signaling terminals are removed, the signaling links of the SSFAs 41 to 44 are inactivated. This inactivated signaling link cannot be assigned another active signaling terminal, so it cannot be newly activated. Information on the signaling terminals among the information maintained by the MSHP 35 for process of the messages is very important. When one MSHP 35 which processes the signaling terminals is inactivated and the other MSHP 35 is subject to process of the signaling terminals of the inactivated MSHP 35, a failure of managing the signaling terminals results in loss of the messages.
Accordingly, the conventional technology which do not have a function of automatically assigning signaling terminals cannot activate signaling links which have been inactivated due to inactivation of the signaling terminals assigned thereto, thereby making it difficult to manage the signaling network. Namely, error in the ITU-T No. 7 signaling system makes the switching center come to a stop. When the signaling link is inactivated because of the trouble in the corresponding signaling terminal, the conventional technology not having an automatic assigning function has a serious problem in managing the signaling network.